Field of the Invention
The present application relates to a lead- and alkali metal-free piezoelectric ceramic and a method for manufacturing the same. The present application also relates to a piezoelectric element, a vibration device, a liquid ejecting head, a liquid ejecting apparatus, an ultrasonic motor, an optical apparatus, a vibration unit, a dust removing unit, an image sensing apparatus and an electronic apparatus, each using the piezoelectric ceramic.
Description of the Related Art
Piezoelectric ceramics are typically metal oxides having a perovskite structure, such as lead zirconate titanate (hereinafter referred to as PZT). PZT however contains lead, which impacts on environment. This is an issue. Accordingly, lead-free piezoelectric ceramics are desired.
Barium titanate has been known as a lead-free piezoelectric ceramic. Also, in order to improve the characteristics of the lead-free piezoelectric ceramic, barium titanate-based materials have been being developed.
Japanese Patent Laid-Open No. 2009-215111 discloses a barium titanate-based piezoelectric ceramic in which Ca is substituted for part of the A site of barium titanate and Zr is substituted for part of the B site of the barium titanate to enhance the piezoelectric properties of the barium titanate. Such a material is superior to barium titanate in terms of piezoelectric constant, but has a low mechanical quality factor.
Japanese Journal of Applied Physics, 2010, vol. 49, 09MD03-1 to 09MD03-4, discloses barium titanate-based materials containing Ca substituted for part of the A site of barium titanate and further containing Mn and Fe, or Cu. Such a material is superior to barium titanate in terms of mechanical quality factor, but the electromechanical coupling factor k31 thereof is as low as 0.119.
The piezoelectric ceramics in the known art do not satisfy both the demands for mechanical quality factor and electromechanical coupling factor, and piezoelectric elements using such a piezoelectric ceramic undesirably consume large power.